Legit Reviews posted a review of the ASUS K42F Notebook w/ Intel Core i5 540M Arrandale CPU. Here's a bit:

The ASUS K42F-B1 14-inch notebook was amazing to use! This notebook is very fast as you saw from the numerous benchmarks that we threw at the Intel Core i5 540M processor. When the dust settled the Intel Core i5 540M was on average 40-50% faster than Intel Core 2 Duo P8700 processor. This is due to the fact that the Arrandale processor has HyperThreading technology and therefore twice as many threads, but it also has to do with Turbo Mode and the Intel HD Graphics. When it comes to Blu-ray playback, gaming or Croptography performance the Arrandale processor really looked great and is no doubt a processor that has plenty of muscle behind it.

The notebook isn't all muscle though as it has great power consumption numbers and the idle power consumption is excellent. Having the ASUS K42F idle at just 15 Watts just brings a smile to your face. Intel has done a great job with the dynamic power management on the CPU and the GPU in Arrandale. The entire world is trying to reduce their energy footprint, so if conserving power is something that matters to you then look no further. Although, if you want to watch a two-hour long Blu-ray our testing showed you need at least an 8-cell battery and that got us just a tad over 2 hours and 10 minutes in balanced battery mode.

The Intel HD Graphics is still not going to get die-hard gamers and enthusiasts excited, but it is a step forward. In 3DMark Vantage we saw a 51% performance improvement and that carried over to real world game performance as well as in Spore we noted a 51% performance improvement at 1280x720 with the game set to high image quality. Just for fun I ran around in Spore on both the Intel Core i5 540M and the Intel Core 2 Duo P8700 powered notebooks at the same time and the difference was amazing. The notebook with the Intel Core i5 540M was much smoother and the game looked and felt much better. For mainstream and entry level game titles like Spore and Sims 3, a notebook with Intel HD Graphics is all you really do need in order to play!